Qualaquin (Quinine Sulfate)

Qualaquin (Quinine Sulfate) Medication Information

Uses

Quinine (quinine sulfate) is a prescription medication used to treat malaria.  Its brand name is Qualaquin.   

Malaria can be a life-threatening infection.  It is usually transmitted by a bite from a mosquito infected with the parasite Plasmodium falciparum.  When the mosquito bites, the parasite is released into the bloodstream and infects its host’s red blood cells.  It may take weeks or months before malaria symptoms start but may include fever, chills, headache, upset stomach, muscle pain, and fatigue (lack of energy).  If untreated, the infection can lead to swelling of blood vessels in the brain and multiple organ failures.

Infected mosquitos are more common in tropical regions.  Talk to your doctor if you’re traveling to an area where malaria is prevalent. They may prescribe medications to take before, during, and after the trip to prevent disease.  It’s also important to take steps to help avoid mosquito bites, such as using a mosquito net for sleeping, protective clothing, and insect repellent.

Dosage

Qualaquin is an oral capsule that contains quinine sulfate. It comes in one strength: 324 mg.

The usual dosage of Qualaquin to treat malaria is two capsules (648 mg) every 8 hours for 7 days.

Take quinine exactly as prescribed by your doctor.

Precautions

Taking quinine may cause harmful effects in some people.  Be sure to let your doctor know if you have any of the following health conditions before taking Qualaquin:

• Heart rhythm problems, especially prolongation of QT interval
• G6PD deficiency
• Myasthenia gravis
• Optic neuritis
• Bleeding problems
• Kidney or liver disease
• Pregnant, planning to become pregnant, or breastfeeding
• Previous allergic reaction to hypersensitivity to quinine, mefloquine, or quinidine

Side Effects

Like all medications, quinine has risks of mild and severe side effects.  

Most people experience some mild side effects of quinine that go away when treatment is stopped.  A few examples include:

• Headache
• Increased sweating
• Nausea
• Tinnitus (ringing in the ears)
• Decreased hearing ability
• Dizziness
• Blurred vision
• Vomiting
• Diarrhea
• Stomach pain

Less commonly, people taking quinine could have more severe side effects, such as:

• Deafness
• Blindness
• Rapid or abnormal heart beat that could lead to death

Interactions

Several medications can cause harmful drug interactions with quinine.  Some of these drugs should not be taken with quinine.  Others may be taken if your doctor closely monitors you. A few examples include:

• Antacids containing aluminum or magnesium
• Antiepileptics such as carbamazepine, phenobarbital, and phenytoin
• Digoxin
• Neuromuscular blocking agents such as pancuronium and succinylcholine
• Rifampin
• Ritonavir
• Warfarin

Check with your doctor or pharmacist before starting any new medications or natural supplements while taking quinine.

Storage

Store quinine at room temperature (20° to 25ºC/68° to 77°F) in a tightly-closed container.

Pharmacists Tips

• Take quinine with food to help prevent stomach upset.
• If you forget to take a dose, do not double the next dose. 
• If it’s been more than 4 hours since the missed dose, just wait and take your regular amount at your next scheduled time.

Quinine FAQs

Can I take quinine to help prevent or relieve nighttime leg cramps?

Historically, quinine has been used to treat nighttime leg cramps.  In 2007, the Food and Drug Administration banned the sale of over-the-counter products containing quinine in the United States.  The ban was based on evidence that quinine is associated with severe adverse events and drug interactions, some fatal.  Quinine is available over-the-counter in other countries. Still, it’s essential to consult your doctor before taking it, especially if you have a history of heart problems or take other medications.

If you have nighttime leg cramps, there are other options you may want to try.  Muscle cramps are often caused by dehydration.  Try increasing your water intake during the day to at least 60 ounces daily.  Another option is tonic water, which contains a small amount of quinine.  If nighttime leg cramps persist, be sure to talk to your doctor.  They may determine other causes of your leg cramps that can be relieved by different treatment types. 

References

1. Questions and Answers about FDA’s Enforcement Action Against Unapproved Quinine Products. FDA. 2006. https://www.fda.gov/media/75097/download Accessed January 31, 2021.
2. Qualaquin (quinine sulfate) Prescribing Information. Philadelphia, PA; Mutual Pharmaceutical Company, Inc.: 2014. https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/021799s024lbl.pdf Accessed January 31, 2021.
3. Malaria. Mayo Clinic Staff: 2018. https://www.mayoclinic.org/diseases-conditions/malaria/symptoms-causes/syc-20351184  Accessed January 31, 2021.